Almost 40% of placebo-treated patients participating in the drug trials got better after receiving dummy pills, compared to 15% of patients in the sham-therapy portions of the non-pharmaceutical trials.
Since drugs used to treat migraines and other recurring headaches can have side effects, study co-author Bart W. Koes, PhD, says the findings suggest that many patients might benefit from non-pharmaceutical interventions.
Koes is a professor of general practice medicine at Erasmus Medical Center in Rotterdam.
"Patient expectations appear to have a lot to do with outcomes," Koes tells WebMD. "If we understood more about why this placebo effect occurs it could impact both clinical practice and future research."
Placebo Effect in Migraine Patients
More than nine out of 10 people experience occasional or frequent headaches, and various drug treatments, lifestyle interventions, and alternative approaches are used to treat and prevent head pain.
Tension headaches, which account for about 90% of all headaches, typically originate in the neck, upper back, or other muscle groups, while migraines most often involve pulsating pain on one side of the head and may also include nausea, vomiting, and sensitivity to light or sound.
The newly reported analysis included data on more than 7,000 patients with migraines or tension headaches participating in 119 clinical trials of pharmaceutical and non-pharmaceutical headache treatments.
The placebo effect was highest for trials involving drug treatments given to children. Almost half (45%) of children in the placebo arms of these trials got better after taking the dummy pills, compared to 36% of adults.
The placebo effect was also greater in trials involving migraine patients, with almost 41% of these patients who got the sham treatments or no treatment recovering, compared to 34% of tension headache patients.
While the research suggests that patients who unknowingly take placebo pills have better outcomes than those who get no treatment at all, the researchers acknowledge that "a placebo cannot easily be prescribed in daily practice."
The research analysis appears in the June issue of the Journal of Manipulative and Physiological Therapeutics.